The accuracy of the eigenvectors computed by using the Nyström's method strongly depends on the
selection of the \(k\)  columns of \(W\)  corresponding to sample \(\mathcal {X}\) . Therefore, different schemes have been considered in the literature,
for instance random sampling, uniform sampling, max-min farthest point sampling and greedy sampling [1]}, [2]},
[3]},[4]},[5]}.
